Probe cards are apparatuses, each including a substrate and probes arranged on the substrate, are used for electrical characteristics of microscopic electronic devices (e.g., semiconductor devices). As well known in this art, semiconductor devices include pads formed on their surfaces for exchanging signals with external electronic systems. Semiconductor devices conduct predetermined operations with electrical signals input through pads and thereafter transfer operation results to the external electronic systems through the pads. During this, the probe cards provide electric paths between the semi-conductor devices and the external electronic systems (e.g., testers), enabling electric tests to the semiconductor devices.
In the mean time, with higher integration density of semiconductor devices, those pads are being more microscopic in dimensions and reduced even in intervals therebetween. According as that, the probe cards need to be fabricated in finer configurations in correspondence with such high integration density of semiconductor devices, but these requirements for miniaturation make fabrication processes of the probe cards more difficult. Especially, coupling processes for adhering probes, which are arranged to contact with pads of the semiconductor devices, on a probe card substrate are usually confronted by varieties of technical difficulties along the higher integration density of semiconductor devices.
There are various arts for the coupling processes, such as a soldering conducted by hand, a technique using a flip-chip bonder, and a technique using laser. The soldering by hand takes a long time, as well as a product quality is heavily dependent on skill of a worker. Further, according to the trends of miniaturation on semiconductor devices, the soldering is insufficient to accomplish the accuracy of alignment required therefor.
The technique by the flip-chip bonder is widely used nowadays, but disadvantageous to improving a product yield because just one probe fail thereof may result in an overall defect. Furthermore, since the flip-chip bonding is required of expensive equipment, it raises a cost for manufacturing a product thereof.
The coupling technique by laser includes steps of individually heating and bonding probes, so it takes a long time as like the soldering. And, as the laser coupling technique accompanies with rapidly cooling and rapidly heating probes, it would cause destruction of a product by abrupt temperature variation.
Moreover, while an adhesive is used for settling probes on a substrate of the probe card, those techniques make it difficult to precisely control configuration and bulk of the adhesive in accordance with necessity. This difficulty in controlling pattern and bulk of the adhesive may incur irregularity on height of the probes and degrade the qualities of a probe card. In particular, according to those technical ways for probe cards, since the adhesive used for fixing probes is hard to be formed in predetermined pattern and bulk all over the substrate of probe card, it is difficult to overcome such irregularity on height of the probes.